1. Preheat the oven to 350°F. Wash the duck under cold running water and pat it dry inside and out with paper towels. Remove the large chunks of fat from inside the duck and rub the cavity with 1 teaspoon of the salt. Cut off the loose neck skin and truss the bird securely, then prick the surface around the thighs, the back and the lower part of the breast with a skewer or the tip of a sharp knife.

2. In a heavy 6- to 8-quart casserole, heat 2 tablespoons of the oil over moderate heat until a light haze forms above it. Add the duck and, turning it frequently with a slotted spoon or tongs, cook for about 15 minutes, or until it browns richly on all sides. Pour off the rendered fat and sprinkle the duck all over with the remaining 2 teaspoons of salt.

3. Meanwhile, combine the bell pepper, chilies, onions and water in the jar of an electric blender and blend at high speed for 20 or 30 seconds. Turn the machine off and scrape down the sides of the jar with a rubber spatula. Then blend again until the mixture is completely smooth.

4. In a heavy 10- to 12-inch skillet, heat the remaining ¼ cup of oil over moderate heat. Drop in the garlic and, stirring constantly, cook for 1 or 2 minutes, until it browns lightly. Watch carefully for any sign of burning and regulate the heat accordingly.

5. Add the entire contents of the blender jar and stir over high heat for 2 minutes. Stir in the ginger, laos and turmeric and, stirring frequently, cook briskly until most of the liquid in the pan evaporates and the mixture is thick enough to hold its shape in a spoon.

6. With a spatula, spread the pepper mixture evenly over the duck, cover the casserole and place it on the middle shelf of the oven. Roast for 45 minutes, then remove the cover, pour the tamarind water into the cooking liquid, and baste the bird thoroughly. Roast the duck uncovered for 30 minutes longer, basting it every 10 minutes or so.

7. To test for doneness, pierce the thigh of the bird with the tip of a small, sharp knife. The juice should trickle out a clear yellow; if it is slightly pink, roast the bird for an-other 5 to 10 minutes. Transfer the duck to a heated platter and let it rest for 10 minutes before carving.